Add parameter 'version' to both 'template::head::add_css' and 'template::head::flush_link', in order to add a version to certain resources, as a query parameter, to perform 'cache busting' and forcing retrieval of stale files by the browser
Do not assume a package is installed only if it has an entry in the 'apm_package_types' table. This fixes the issue of package upgrade prompting, in not installed packages, that still have an entry in 'apm_package_types'